Golf club head with polymeric hosel

ABSTRACT

A golf club head includes a face, a club head body, and a hosel. The hosel has a tubular hosel body extending along a longitudinal axis and defining a bore. The bore is configured to receive a golf club shaft or a shaft adapter. The tubular hosel body is molded from a polymeric material that includes a resin and a plurality of fibers, each fiber has a length of from about 0.01 mm to about 12 mm.

CROSS-REFERENCES

This is a divisional of U.S. patent application Ser. No. 14/724,373,filed May 28, 2015, all of which is incorporated herein by reference inits entirety.

TECHNICAL FIELD

The present invention relates generally to a golf club head having apolymeric hosel.

BACKGROUND

A golf club may generally include a club head disposed on the end of anelongate shaft. During play, the club head may be swung into contactwith a stationary ball located on the ground in an effort to project theball in an intended direction and with a desired vertical trajectory.

Many design parameters must be considered when forming a golf club head.For example, the design must provide enough structural resilience towithstand repeated impact forces between the club and the ball, as wellas between the club and the ground. The club head must conform tomaximum size requirements set by different rule setting associations,and the face of the club must not have a coefficient of restitutionabove a predefined maximum (measured according to applicable standards).Assuming that certain predefined design constraints are satisfied, aclub head design is typically quantified by the magnitude and locationof the center of gravity, as well as the head's moment of inertia aboutthe center of gravity and/or the shaft.

The club's moment of inertia relates to the club's resistance torotation (particularly during an off-center hit), and is often perceivedas the club's measure of “forgiveness.” In typical driver designs, highmoments of inertia are desired to reduce the club's tendency to push orfade a ball. Achieving a high moment of inertia generally involvesplacing mass as close to the perimeter of the club as possible (tomaximize the moment of inertia about the center of gravity), and asclose to the toe as possible (to maximize the moment of inertia aboutthe shaft).

While the moment of inertia affects the forgiveness of a club head, thelocation of the center of gravity behind the club face (and above thesole) generally affects the trajectory of a shot for a given face loftangle. A center of gravity that is positioned as far rearward (away fromthe face) and as low (close to the sole) as possible typically resultsin a ball flight that has a higher trajectory than a club head with acenter of gravity placed more forward and/or higher.

While a high moment of inertia is obtained by increasing the perimeterweighting of the club head, an increase in the total mass/swing weightof the club head (i.e., the magnitude of the center of gravity) has astrong, negative effect on club head speed and hitting distance. Saidanother way, to maximize club head speed (and hitting distance), a lowertotal mass is desired; however a lower total mass generally reduces theclub head's moment of inertia (and forgiveness).

In the tension between swing speed (mass) and forgiveness (moment ofinertia), it may be desirable to place varying amounts of mass inspecific locations throughout the club head to tailor a club'sperformance to a particular golfer or ability level. In this manner, thetotal club head mass may generally be categorized into two categories:structural mass and discretionary mass.

Structural mass generally refers to the mass of the materials that arerequired to provide the club head with the structural resilience neededto withstand repeated impacts. Structural mass is highlydesign-dependant, and provides a designer with a relatively low amountof control over specific mass distribution. On the other hand,discretionary mass is any additional mass that may be added to the clubhead design for the sole purpose of customizing the performance and/orforgiveness of the club. In an ideal club design, the amount ofstructural mass would be minimized (without sacrificing resiliency) toprovide a designer with a greater ability to customize club performance,while maintaining a swing weight that is expected by the consumer.

SUMMARY

A golf club head includes a face, a club head body, and a hosel. Thehosel has a tubular hosel body extending along a longitudinal axis anddefining a bore. The bore is configured to receive a golf club shaft ora shaft adapter. The tubular hosel body is molded from a polymericmaterial that includes a resin and a plurality of fibers, each fiber hasa length of from about 0.01 mm to about 12 mm.

In one configuration, a method of manufacturing a polymeric hosel for agolf club head includes molding a tubular hosel body from a polymericmaterial. The tubular hosel body is molded about a longitudinal axis anddefines a bore configured to receive a golf club shaft or a shaftadapter. Additionally, the polymeric material comprises a resin and aplurality of fibers that each have a length of from about 0.01 mm toabout 12 mm. The resin is preferably of thermoplastic, and may be acarbon-filled polyamide.

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of a golf club having a detachableface.

FIG. 2 is a schematic partial cross-sectional view of the hosel of FIG.1, taken along line 2-2.

FIG. 3 is a schematic enlarged view of a portion of the area marked“FIG. 3” provided in FIG. 2, illustrating embedded fiber orientation.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numerals are used toidentify like or identical components in the various views, FIG. 1illustrates a schematic perspective view of a wood-type golf club head10 (i.e., “club head 10”) that generally includes a face portion 12(i.e., the “face 12”) and a body portion 14 (i.e., the “body 14”). Asgenerally illustrated in FIG. 1, the club head 10 may be mounted on theend of an elongate shaft 16, which may be gripped and swung by a user toimpart a generally arcuate motion to the club head 10.

The face 12 of the club head 10 generally forms the leading surface ofthe club head 10 and has a slight convex/arcuate curvature that extendsout from the club head 10. In one embodiment, the curvature (i.e., bulgeand/or roll) of the face 12 has a radius of from about 7 inches to about20 inches. Additionally, as is commonly understood, the face 12 may bedisposed at an angle to a vertical plane when the club is held in aneutral hitting position. This angle may be generally referred to as theloft angle or slope of the club. Wood-type club heads (including hybridwoods), such as illustrated in FIG. 1, may most commonly have a loftangle of from about 8.5 degrees to about 24 degrees, though other loftangles are possible and have been commercially sold.

The body 14 of the club head 10 may generally be configured to supportthe face 12 and to aid in coupling the face 12 to the elongate shaft 16.The face 12 may be secured to the body 14, for example, through the useof adhesives, mechanical fasteners 30, or welding (i.e., if similarmaterials are used for the face 12 and body 14). Because an impact witha ball can generate considerably large stresses near the point ofimpact, in one configuration, the face 12 may be formed from one or moremetallic materials that are suitable to withstand any expected impactloading. Examples of suitable materials may include, but are not limitedto, various alloys of stainless steel or titanium.

Referring again to FIG. 1, the body 14 may generally include a lowerportion 22 (i.e., a “sole 22”) and an upper portion 24 (i.e., a “crown24”). For the purpose of this description, the crown 24 may meet thesole 22 where the surface has a vertical tangent when the club head 10is held in a neutral hitting position (i.e., a position where the shaft16 is maintained entirely in a vertical plane and at a prescribed lieangle relative to a horizontal ground plane). Finally, the club head 10includes a hosel 26 that is configured to receive the golf club shaft 16or a suitable shaft adapter 28.

To reduce structural mass beyond what is economically viable with metalalloys, the body 14 of the club head 10 may be formed from a polymericmaterial. The comparatively low density nature of polymeric materialsalso permits greater design flexibility, at less of a structural weightpenalty, than similar designs made from metal. In one configuration, thedesired design flexibility may be achieved by molding the polymericmaterial into shape using a molding technique, such as, injectionmolding, compression molding, blow molding, thermoforming or the like.To provide the maximum design flexibility, the preferred moldingtechnique is injection molding.

While weight savings and design flexibility are important, the polymericmaterial must still be strong enough to withstand the stress that isexperienced when the club head 10 impacts a ball. This may beaccomplished through a combination of structural and material designchoices. With regard to material selection, it is preferable to use amoldable polymeric material that has a tensile strength of greater thanabout 200 MPa (according to ASTM D638), or more preferably greater thanabout 250 MPa.

In one embodiment, the body 14 may be formed from a polymeric materialthat comprises a resin and a plurality of discontinuous fibers (i.e.,“chopped fibers”). The discontinuous/chopped fibers may include, forexample, chopped carbon fibers or chopped glass fibers and are embeddedwithin the resin prior to molding the body 14. In one configuration, thepolymeric material may be a “long fiber thermoplastic” where thediscontinuous fibers are embedded in a thermoplastic resin and each havea designed fiber length of from about 3 mm to about 12 mm. In anotherconfiguration, the polymeric material may be a “short fiberthermoplastic” where the discontinuous fibers are similarly embedded ina thermoplastic resin, though may each have a designed length of fromabout 0.01 mm to about 3 mm. In either case, the fiber length may beaffected by the molding process, and due to breakage, some may beshorter than the described range. Additionally, in some configurations,discontinuous chopped fibers may be characterized by an aspect ratio(e.g., length/diameter of the fiber) of greater than about 10, or morepreferably greater than about 50, and less than about 1500. Regardlessof the specific type of discontinuous chopped fibers used, the materialmay have a fiber length of from about 0.01 mm to about 12 mm and a resincontent of from about 40% to about 90% by weight, or more preferablyfrom about 55% to about 70% by weight.

One suitable material may include a thermoplastic polyamide (e.g., PA6or PA66) filled with chopped carbon fiber (i.e., a carbon-filledpolyamide). Other resins may include certain polyimides,polyamide-imides, polyetheretherketones (PEEK), polycarbonates,engineering polyurethanes, and/or other similar materials.

In one configuration, the body 14 may be entirely molded through asingle process. If complex geometries are desired, molding techniquessuch as lost core molding or injection molding with collapsible slidesmay be used to form any internal recesses or cavities. In anotherconfiguration, instead of a unitary design, the body 14 may be formed astwo or more portions that are subsequently joined together. Such amulti-piece design may reduce the complexity of the molding process, butmay add additional manufacturing steps to fuse the components together.

Referring to FIG. 2, the hosel 26 generally includes a tubular hoselbody 40 that is aligned along a longitudinal axis 42 and that defines acentral bore 44 that is configured to receive the shaft 16 or shaftadapter 28. If the hosel body 40 is configured to directly receive theshaft 16, the bore 44 may have a diameter of from about 8.5 mm to about9.5 mm. If instead, the hosel body 40 is configured to receive a shaftadapter 28, the bore 44 may have a diameter of from about 8.5 mm toabout 20 mm, or from about 10 mm to about 15 mm. Additionally, the bore44 may have a depth, measured along the longitudinal axis 42, of fromabout 20 mm to about 40 mm, or from about 25 mm to about 35 mm.

As shown, the tubular hosel body 40 generally extends between a firstend 46 and a second end 48. The first end 46 defines a first opening 50through which the golf club shaft 16 or shaft adapter 28 may be insertedinto the bore 44. The first opening 50 may have a similar diameter asthe bore, or may define a slightly larger and/or chamfered ingresssurface. In one configuration, the second end 48 may define a secondopening 52 that has a smaller diameter than the first opening 50. Thesecond opening 52 may, for example, be dimensioned to allow a threadedportion 54 of a screw 56 to extend into the bore 44, but may prevent ahead 58 of the screw 56 from entering. The screw 56 may be operative tosecure an end of the shaft 16 or shaft adapter 28 to the second end 48of the tubular hosel body 40 such that the shaft 16 or shaft adapter 28is restrained from being withdrawn from the bore 44.

In one configuration, an internal surface 58 of the hosel body 40 mayinclude a plurality of splines 60. The plurality of splines 60 may bedirectly adjacent to the first end 46, and may be operative to inhibitrelative rotation between the shaft 16 or shaft adapter 28 and the hoselbody 40 when the shaft 16 or shaft adapter 28 is inserted into the bore44. Each respective spline 60 may have a height or depth of, forexample, from about 0.25 mm to about 0.5 mm.

To further reduce the structural weight of the golf club head 10, thehosel 26, and specifically the tubular hosel body 40, may be molded froma polymeric material that includes both a resin and a plurality ofdiscontinuous/chopped fibers. The chopped fibers may include choppedcarbon fibers or chopped glass fibers and are embedded within the resinprior to molding the body 14. In one configuration, the polymericmaterial used to form the hosel body 40 may be a “long fiberthermoplastic” or a “short fiber thermoplastic” that desirably has afiber length of from about 0.01 mm to about 12 mm and a resin content offrom about 40% to about 90% by weight, or more preferably from about 55%to about 70% by weight.

One suitable material for the hosel body 40 may include a thermoplasticpolyamide (e.g., PA6 or PA66) filled with chopped carbon fiber (i.e., acarbon-filled polyamide). Other resins may include certain polyimides,polyamide-imides, polyetheretherketones (PEEK), polycarbonates,engineering polyurethanes, and/or other similar materials.

Because the hosel 26 is generally a high-stress portion of the club head10, it is important to ensure that the design of the polymeric hosel isstrong enough to repeatedly withstand expected impact forces. To providean optimized design that achieves the required strength at the lowestpossible weight, it is preferable to align as many of the embeddedreinforcing fibers in a parallel orientation with the longitudinal axis42 as possible. While it is not likely possible to achieve 100% of thefibers in perfect alignment, it is preferable to achieve a fiberorientation throughout the hosel body 40 where at least 50% of thefibers have an average longitudinal orientation within about 30 degreesof parallel to the longitudinal axis 42 of the bore 44. In other, evenmore preferred embodiments, at least 60% of the fibers are orientedwithin about 20 degrees of parallel, or at least 70% of the fibers areoriented within about 10 degrees of parallel to the longitudinal axis42.

FIG. 3 schematically illustrates a plurality of chopped fibers 70embedded within a polymer resin 72 to form the wall 74 of the hosel body40. As shown, each fiber 70 may have a length 76 that is from about 0.01mm to about 12 mm (note that the illustrated fibers are not necessarilyillustrated to scale in either size or density). During a moldingprocess, such as injection molding, embedded fibers 70 tend to alignwith a direction of the flowing polymer. With some fibers (i.e.,particularly with short fiber thermoplastics) and resins, the alignmenttends to occur more completely close to the walls of the mold or edge ofthe part. These layers are referred to as shear layers 78 or skinlayers. Conversely, within a central core layer 80, the fibers 70 cansometimes be more ramdomized and/or perpendicular to the flowingpolymer. In these embodiments, the thickness 82 of the core layer 80 canbe altered by various molding parameters including molding speed (i.e.,slower molding speed can yield a thinner core layer 80) and mold design.With the present design, it is desirable to minimize the thickness 82 ofany randomized core layer 80.

To align the most number of fibers 70 in a parallel orientation with thelongitudinal axis 42 of the bore 44, it may be desirable to mold thehosel body 40 with a mold flow that is also parallel with thelongitudinal axis 42. In one embodiment, this may be achieved by gatinga corresponding mold proximate to the second end 48 of the hosel body 40and venting the mold proximate to the first end 46. For example, asshown in FIG. 2, the hosel body 40 may be gated at 84 and vented at 86.Such a mold design would allow the polymeric material to encircle thesecond end 48 to form the ledge 88, after which it may uniformly flowtoward the first end 46.

In this design, the splines 60 may be integrally molded with the tubularhosel body 40. Additionally, the hosel 26 may be either integrallymolded with the body 14, or could be separately molded and attached viaa joining method such as welding or adhering.

In one configuration, a method of manufacturing a polymeric hosel 26 fora golf club head 10 includes molding a tubular hosel body 40 from apolymeric material. The tubular hosel body 40 is molded about alongitudinal axis 42 and defines a bore 44 configured to receive a golfclub shaft 16 or a shaft adapter 28. Additionally, the polymericmaterial comprises a resin 72 and a plurality of fibers 70 that eachhave a length 76 of from about 0.01 mm to about 12 mm. The resin ispreferably of thermoplastic, and may be a carbon-filled polyamide.

Molding the tubular hosel body 40 may include injecting the polymericmaterial into a mold such that it flows from a first end 46 of thetubular hosel body 40 to a second end of the tubular hosel body 48. Topromote a more uniform flow, the mold may be vented at the second end 48of the tubular hosel body 40. In one configuration, at least 50% of theplurality of fibers to be oriented within about 30 degrees of parallelto the longitudinal axis of the bore.

When formed in this manner, the hosel 26 may avoid any need for metallicinserts to be secured within the bore 44 or for ancillary metallic hoselsupports. Testing of a molded polymeric hosel 26 with a splined,polymeric shaft adapter 28 passed multiple durability tests, performedcumulatively on the same hosel 26, without any signs of compromisedhosel integrity or significant wear. The cumulative testing included3000 impacts (of progressively increasing speed) between the face 12 anda golf ball, followed by robot swing testing, and numerousinsertion/removal cycles of the shaft adapter 28.

“A,” “an,” “the,” “at least one,” and “one or more” are usedinterchangeably to indicate that at least one of the item is present; aplurality of such items may be present unless the context clearlyindicates otherwise. All numerical values of parameters (e.g., ofquantities or conditions) in this specification, including the appendedclaims, are to be understood as being modified in all instances by theterm “about” whether or not “about” actually appears before thenumerical value. “About” indicates that the stated numerical valueallows some slight imprecision (with some approach to exactness in thevalue; about or reasonably close to the value; nearly). If theimprecision provided by “about” is not otherwise understood in the artwith this ordinary meaning, then “about” as used herein indicates atleast variations that may arise from ordinary methods of measuring andusing such parameters. In addition, disclosure of ranges includesdisclosure of all values and further divided ranges within the entirerange. Each value within a range and the endpoints of a range are herebyall disclosed as separate embodiment. The terms “comprises,”“comprising,” “including,” and “having,” are inclusive and thereforespecify the presence of stated items, but do not preclude the presenceof other items. As used in this specification, the term “or” includesany and all combinations of one or more of the listed items. When theterms first, second, third, etc. are used to differentiate various itemsfrom each other, these designations are merely for convenience and donot limit the items.

1. A golf club head comprising: a face, a club head body, and a hosel;wherein the hosel includes a tubular hosel body having a longitudinalaxis and defining a bore configured to receive a golf club shaft or ashaft adapter; wherein the tubular hosel body is molded from a polymericmaterial comprising a resin and a plurality of discontinuous fibers. 2.The golf club head of claim 1, wherein each of the plurality ofdiscontinuous fibers has a length of from about 0.01 mm to about 12 mm.3. The golf club head of claim 1, wherein at least 50% of the pluralityof discontinuous fibers are oriented within about 30 degrees of parallelto the longitudinal axis.
 4. The golf club head of claim 1, wherein thebore has a diameter of from about 8.5 mm to about 20 mm, and a length offrom about 25 mm to about 35 mm.
 5. The golf club head of claim 1,wherein the tubular hosel body has a first end and a second end; whereinthe first end defines a first opening that permits the golf club shaftor the shaft adapter to be inserted into the bore; and wherein thesecond end defines a second opening that is smaller than the firstopening, and wherein the second opening is operative to permit athreaded portion of a screw to extend through the second end into thebore.
 6. The golf club head of claim 5, wherein the hosel includes aplurality of splines that are integrally molded with the tubular hoselbody and directly adjacent to the first end; wherein the plurality ofmolded splines are on an internal surface of the tubular hosel body andare operative to inhibit rotation of the golf club shaft or the shaftadapter following insertion into the bore.
 7. The golf club head ofclaim 1, wherein the polymeric material is from about 40% to about 90%resin by weight.
 8. The golf claim head of claim 1, wherein the resin isa thermoplastic polymer.
 9. The golf club head of claim 1, wherein thepolymeric material is a carbon-filled polyamide.
 10. The golf club headof claim 1, wherein the each of the plurality of fibers has a length offrom about 0.01 mm to about 3 mm.
 11. The golf club head of claim 1,wherein the club head body is formed from the polymeric material and isintegrally molded with the hosel.